A conventional pressure tank contains a container containing purified water therein, and a connector mounted on a top of the container and connected to a water pipe for input and output of the purified water. The connector includes a hollow threaded head soldered on the top of the container and screwed into a connecting nut of the water pipe, a copper tube having an upper portion secured in the threaded head and a lower portion riveted on an inner side of the top of the container, and a leakproof ring mounted between the inner side of the top of the container and the lower portion of the copper tube.
Pressure tanks can be hanged and connected to a water pipe to prevent water hammer effect. However, the connector bears the weight of the pressure tank and vibration of the tank caused by movements of the water into or out of the tank. Stress is concentrated in the connector portion and may cause damage to the connection. The connector may break or crack and cause water leakage. Besides, when the copper tube is wet, it easily produces verdigris that will do damage to the human body. In addition, the threaded head of the connector cannot be soldered on the top of the container easily and conveniently, thereby causing inconvenience to the operator. Further, the copper tube has a constant wall thickness, so that when the leakproof ring is mounted on the lower portion of the copper tube and the copper tube is riveted to press the leakproof ring during the riveting process, the lower portion of the copper tube is easily deviated due to an uneven pressure distribution, so that the leakproof ring is easily detached from the lower portion of the copper tube during the riveting process, thereby causing a water leakage. Therefore a pressure tank having a reinforced connector with a watertight structure is needed.